Free Tool
Break-Even ACoS Calculator
The exact ACoS where an ad-driven sale stops making you money. Every formula is shown below. No email, no signup, no catch.
Your numbers (per unit)
Break-even ACoS
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Above this, every ad-driven sale loses money.
Contribution / unit
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Contribution margin
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Target ACoS to keep 15% contribution margin after ads
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What your number actually means
Enter your numbers above, then I'll tell you what your break-even ACoS says about how much attention you can afford to buy.
Every formula, shown
Amazon referral fee = price × referral%
Total cost/unit = COGS + referral fee + FBA fee + other
Contribution/unit = price − total cost/unit
Contribution margin = contribution/unit ÷ price
Break-even ACoS = contribution margin
Target ACoS = break-even ACoS − contribution margin you want after ads
Results use the costs you enter. They do not include fixed overhead, taxes, or any costs you leave out, so contribution margin is not company net profit.
Why it matters: ACoS on its own tells you nothing about profit. A "good" 25% ACoS is bleeding money on a thin-margin product and printing cash on a fat-margin one. Break-even ACoS is the line. Margin protection, one of the five pillars of the AMDC Growth System, is about knowing this number for every SKU and bidding to it.
Want this run across your whole catalog?
A Profit & Growth Teardown reviews the product and advertising inputs you can share, then prioritizes margin questions and next steps. $500, credited toward your first month if we work together.
Prefer to talk first? Book a free 15-minute call.
Talk directly with Aleks about fit and scope.